This site has the tag memory, which is currently tagged on 17 questions and is very ambiguous. By my count, the questions are about the following:
- Amnesia/Memory loss, 4
- Specific memory removal, 2
- Memory charm (Harry Potter), 3
- Reliving a memory, 3
- Memory transfer from one individual to another, 2
- Memory recording, 1
- Recalling a lost memory, 1
- Eidetic memory, 1
Some of these are about the general concept of remembering something (e.g. eidetic memory), others are about a recollection of an event and what you do with it, and others are about a spell.
One of the main points in Jeff Atwood's guidelines for good tags is that a tag should have a clear, unambiguous definition and mean the same thing in all contexts. The fact that this tag has been used for eight different contexts indicates that it does not meet this criteria. Additionally, it can't stand on its own, so it's likely a meta tag.